Hi Arnd, LGTM.
-----Original Message----- From: Arnd Bergmann <[email protected]> Sent: Wednesday, June 19, 2019 8:51 AM To: Corey Minyard <[email protected]>; Greg Kroah-Hartman <[email protected]> Cc: Arnd Bergmann <[email protected]>; Asmaa Mnebhi <[email protected]>; Vadim Pasternak <[email protected]>; Corey Minyard <[email protected]>; [email protected]; [email protected] Subject: [PATCH] ipmi: ipmb: don't allocate i2c_client on stack The i2c_client structure can be fairly large, which leads to a warning about possible kernel stack overflow in some configurations: drivers/char/ipmi/ipmb_dev_int.c:115:16: error: stack frame size of 1032 bytes in function 'ipmb_write' [-Werror,-Wframe-larger-than=] There is no real reason to even declare an i2c_client, as we can simply call i2c_smbus_xfer() directly instead of the i2c_smbus_write_block_data() wrapper. Convert the ipmb_write() to use an open-coded i2c_smbus_write_block_data() here, without changing the behavior. It seems that there is another problem with this implementation; when user space passes a length of more than I2C_SMBUS_BLOCK_MAX bytes, all the rest is silently ignored. This should probably be addressed in a separate patch, but I don't know what the intended behavior is here. Fixes: 51bd6f291583 ("Add support for IPMB driver") Signed-off-by: Arnd Bergmann <[email protected]> --- drivers/char/ipmi/ipmb_dev_int.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/char/ipmi/ipmb_dev_int.c b/drivers/char/ipmi/ipmb_dev_int.c index 2895abf72e61..c9724f6cf32d 100644 --- a/drivers/char/ipmi/ipmb_dev_int.c +++ b/drivers/char/ipmi/ipmb_dev_int.c @@ -117,7 +117,7 @@ static ssize_t ipmb_write(struct file *file, const char __user *buf, { struct ipmb_dev *ipmb_dev = to_ipmb_dev(file); u8 rq_sa, netf_rq_lun, msg_len; - struct i2c_client rq_client; + union i2c_smbus_data data; u8 msg[MAX_MSG_LEN]; ssize_t ret; @@ -138,17 +138,17 @@ static ssize_t ipmb_write(struct file *file, const char __user *buf, /* * subtract rq_sa and netf_rq_lun from the length of the msg passed to - * i2c_smbus_write_block_data_local + * i2c_smbus_xfer */ msg_len = msg[IPMB_MSG_LEN_IDX] - SMBUS_MSG_HEADER_LENGTH; - - strcpy(rq_client.name, "ipmb_requester"); - rq_client.adapter = ipmb_dev->client->adapter; - rq_client.flags = ipmb_dev->client->flags; - rq_client.addr = rq_sa; - - ret = i2c_smbus_write_block_data(&rq_client, netf_rq_lun, msg_len, - msg + SMBUS_MSG_IDX_OFFSET); + if (msg_len > I2C_SMBUS_BLOCK_MAX) + msg_len = I2C_SMBUS_BLOCK_MAX; + + data.block[0] = msg_len; + memcpy(&data.block[1], msg + SMBUS_MSG_IDX_OFFSET, msg_len); + ret = i2c_smbus_xfer(ipmb_dev->client->adapter, rq_sa, ipmb_dev->client->flags, + I2C_SMBUS_WRITE, netf_rq_lun, + I2C_SMBUS_BLOCK_DATA, &data); return ret ? : count; } -- 2.20.0 _______________________________________________ Openipmi-developer mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/openipmi-developer
